I've seen a few people running into some blockades over this already: a "failed to open stream: HTTP request failed!" error on any file_get_contents function. The weird thing is right after it I get the value I'm looking for from the Arduino that's broadcasting it.

Now, if I use say...Google, as the URL, it works fine. So I'm guessing there's something about the Arduino PHP isn't liking. Is there any specific formatting I could apply to the output of the node that would make this more happy? Or any settings I should be looking at?